Told fibs about first-class head of state that’s acted as intermediary (7)
I believe the answer is:
liaised
'state that's acted as intermediary' is the definition.
I can't judge whether this defines the answer.
'told fibs about first-class head' is the wordplay.
'told fibs' becomes 'lied' (I've seen this in another clue).
'about' is an insertion indicator.
'first class head' becomes 'ais' (I can't justify this - if you can you should give a lot more credence to this answer).
'lied' placed around 'ais' is 'LIAISED'.
'of' acts as a link.
Can you help me to learn more?
(Other definitions for liaised that I've seen before include "Established contacts" , "Maintained contact" , "consulted together" , "Acted as go-between or link" , "Networked" .)